Physics word problem .PLEASE HELP !!!!?

Question

A 4.3 g dart is fired into a block of wood with a mass of 24.2 g. The wood block is initially at rest on a 1.6 m tall post. After the collision, the wood block and dart land 2.9 m from the base of the post. Find the initial speed of the dart.

Answer 1

Time for the block and dart to reach the ground is given by
1.6 = (4.9) t^2
=> t = 4/7 s
If v = horizontal velocity of block and dart,
v * (4/7) = 2.9
=> v = 5.075 m/s
If u = initial velocity of the dart, then by the law of conservation of momentum,
4.3 u = (4.3 + 24.2) * (5.075)
=> u = 33.6 m/s.

Answer 2

The velocity V of the dart and block is the distance S covered from the post in time it takes both block and the dart to fall from the post of height h .

V=S/t

t=sqrt(2h/g)

V=S/sqrt(2h/g)
V=S sqrt(g/2h)
V=2.9 sqrt( 9.81/2 x 1.6)
V=5.1 m/s
Now for law of conservation of momentum
m1Vi= V(m1+m2)
Vi=V(m1+m2)/m1
V1=5.1(4.3 + 24.2)/4.3=33 m/s